Two (thio)semicarbazide compounds, 4-phenyl-1-(pyrid-2-ylmethylene)semicarbazide (PPMSC) and 4-phenyl-1-(pyrid-2-ylmethylene)thiosemicarbazide (PPMTC), were prepared and characterized by elemental analysis, MS, IR, ¹H NMR, UV absorption spectra, solid-state circular dichroism (CD) spectra, and X-ray single-crystal diffraction. The X-ray crystallographic data indicated that PPMSC crystallized in a space group of Sohncke P2₁2₁2₁, PPMSC molecules formed the left-handed helix running along the crystallographic axis a via the intermolecular hydrogen bondings. The solid-state CD spectra and repeated recrystallization revealed that the formation of chiral PPMSC crystals could be regarded as crystallization- induced asymmetric synthesis. Although the crystal structure of PPMTC has not been obtained, PPMTC has the similar properties with PPMSC.

Key words: 4-phenyl-1-(pyrid-2-ylmethylene)semicarbazide, 4-phenyl-1-(pyrid-2-ylmethylene)thio- semicarbazide, chiral symmetry breaking, absolute asymmetric synthesis, chiral crystal, solid-state circular dichroism spectroscopy